The present invention relates to a new and distinct cultivar of Rheum (rhubarb) given the cultivar name ‘Scarlet King’. Rheum is in the family Polygonaceae. This new cultivar is a chance seedling of unknown origin that was discovered during an environmentally controlled indoor breeding program at Sconce Farms in Aurora, Oreg.
Compared to Rheum ‘Deacon’, unpatented, the new cultivar breaks dormancy 2 or more weeks earlier in the Willamette Valley, Oreg. Compared to Rheum ‘Crimson’, unpatented, the new cultivar breaks dormancy 3 or more weeks earlier in the Willamette Valley, Oreg. The new cultivar is also much more frost resistant than either ‘Deacon’ or ‘Crimson’ and has a deeper red color that extends throughout the stalk and into the veins of the leaves early in the growing season.